Hi Lawrence -[quote=“lawrenceyy, post:12, topic:32523”]
If my surface is four-sided, are the other three edges safe during this operation?
No - That is, the opposite edge is safe, depending on the ‘Preserve other end’ setting in the dialog but not the side edges.[quote=“lawrenceyy, post:12, topic:32523”]
What exactly does insertknot do for us in this situation? Insertknot looks a lot like rebuild to me.
It is not really like Rebuild. Inserting knots increases the complexity of a surface or curve- it does not change the 3d shape of the object at all. Rebuild, except in some special cases (like planes) always changes the shape of the object, either a little or a lot. Rebuild results in a uniform object (knot spacing) and InsertKnot rarely does, quite, but with Automatic it does if the input is uniform - Automatic splits every existing span evenly into two. I did not want to change the shape or the structure in the radial direction at all except by MatchSrf, but I needed enough points to be able to match to the target edge reasonably closely, so InsertKnot.